To have an hourglass figure, your waist must be atleast 75% smaller than both your bust and your hips. The traditional "perfect" hourglass figure is 36-24-36, but it's usually said that if your waist in atleast 9" smaller than your bust, which is the same circumference as your hips (or a maximum of 1" larger), then you are an hourglass. Only 8% of women in the world have an hourglass figure!
The hourglass figure is the epitome of feminine beauty, and has been for generations. Some of the most beautiful women in the world boast(ed) them - Marilyn Monroe, Sophia Loren... - and in this day and age when so much controversy surrounds female body shape (is thin in or out?), almost all will agree that the curvy woman is the most beautiful.
You have to be careful about what exercises you do if you wish to achieve an hourglass figure. For example, pilates and sit-ups work towards toning the front of your abdominal muscles to build them to, eventually, a six-pack; this will actually widen your waist. Following the specially designed exercises outlined on this website will help you slim your waist, and also firm your breasts and bum. Follow the instructions on the pages about how often the exercises should be performed weekly.
Hourglass figures are most associated with the glamorous golden-ages of Hollywood, and this style is coming back in to fashion these days...
Bettie Page: 36-24-35
Kelly Brook: 34E-24-34
Marilyn Monroe: 35-22-35
Raquel Welch: 37-22-35
Sophia Loren: 38C-24-38